The present invention relates to a pneumatically movable device with a safety lock means and more specifically to a pneumatically movable device capable of locking a movable member at a specified location, the movable member, such as a chuck holding plate or the like in a robot system for extracting injection molded or die cast products being adapted to be rotated or linearly moved by a pneumatic actuator.
In a prior art robot system for extracting injection molded or die cast products, the chuck holding plate with the chuck means adapted to grip the molded or cast product is caused to be rotated by a pneumatic actuator such as a pneumatic cylinder and may be held at a specified posture by the pneumatic pressure applied to the pneumatic cylinder.
In the prior art chuck holding plate, there have been such problems as the chuck holding plate may be caused to be inclined or otherwise unintentionally moved due to the application of load at a time of rapid vertical movement of the arm of the robot system or due to overload or to any shock aplied to the chuck holding plate in itself or due to leakage of air from the pneumatic cylinder.
Although such method of locking the chuck holding plate at a specified position as by using a pin or the like has been studied, that method was cumbersome.